Solved

Not writing to file

Posted on 2003-11-27
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Last Modified: 2010-04-01
I have a bean with the following constructor, it does not write to the file when used as a bean, but when i create a main method and create an instance of the class and run it as a class the file does not get written to. Why? and how do i make it write to a file when used as a bean

public Taxonamy()
{
      try
      {      
            fw = new FileWriter("taxonamyTree.txt",true);
            fw.write("kjffkjsdafdsj");
            fw.flush();
            fw.close();
      }
      catch(IOException e)
      {
            setError("ERROR OPENING FILE");
      
      }
}
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Question by:danBosh
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16 Comments
 
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Expert Comment

by:jimmack
ID: 9830679
When you say it doesn't write to the file (when used as a bean), do you mean that the exception is thrown or that an empty file is created?

Where is the bean being used?  It may be a permission problem (eg. no write permissions for the directory or file that you are trying to write to).

Try adding the following inside the catch:

System.out.println("IOException from Taxonamy:" + e.toString());

This should give you some more detail about the exception.  (If you're using Tomcat, the output will appear in /logs/catalina.out).
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Expert Comment

by:TimYates
ID: 9830682
My guess would be the constructor is never called when it's used as a bean...

I'm not sure if this is normal behaviour for Beans, but I guess so, as your code is doing it ;-)

Can't you make the file writing a method, and then call invoke method from the JSP?
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Expert Comment

by:jimmack
ID: 9830708
>>  My guess would be the constructor is never called when it's used as a bean.

Not really my area, but is this right?  Surely a bean constructor must be called somewhere.
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Author Comment

by:danBosh
ID: 9830717
tim: i dont think it is that i just put the code in there for simplicity, it didnt work in other locations of the bean either
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Author Comment

by:danBosh
ID: 9830720
and the constructer is called
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Expert Comment

by:jimmack
ID: 9830756
Do you get an exception?
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Author Comment

by:danBosh
ID: 9830782
it doesn't print to the logs and there is no catalina.out in the tomcat directory
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Expert Comment

by:jimmack
ID: 9830851
Are you sure there's no catalina.out?  It should be in the logs directory below the tomcat installation.
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Expert Comment

by:TimYates
ID: 9831033
Sounds like a securityexception...

It could be you dont have write privs to that directory (if you are running on Linux/Unix)

You might also be running Tomcat with the security manager, in which case you'll have to grant rights to create this file...

http://dbforums.com/arch/182/2003/8/731227

(at the bottom)
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Author Comment

by:danBosh
ID: 9831345
jim: yes i perfomed a search for it, and it not there

tim: its windows, ill try that link
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Expert Comment

by:kennethxu
ID: 9831358
>>           fw = new FileWriter("taxonamyTree.txt",true);
The file will be created in the dir that tomcat starts from, most likely in tomcat/bin, not the dir where jsp page is. do you have the write permission in tomcat/bin?
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Author Comment

by:danBosh
ID: 9831380
when i ran the class in command line i created the file taxonamyTree.txt i the web-inf\classes\..\..\ directory where the class is and it wrote to that file, so why would it write to somewhere different when used in conjuntion to a JSP? but ill gp and check anyway
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Accepted Solution

by:
kennethxu earned 40 total points
ID: 9831410
because you current directory of dos windows is in that directory when you run in command line.
when you run in jsp, it's the directory that you start the tomcat.
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Author Comment

by:danBosh
ID: 9831433
outstanding ken, and thanks tim

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Expert Comment

by:kennethxu
ID: 9831444
glad to know your problem is resolved :-)
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Expert Comment

by:TimYates
ID: 9831510
:-)

Good luck!
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